and as our senior international correspondent arwa damon explains, the city's combat zones are expanding each and every day. >> reporter: they are home again, but they are cold and broke and still in danger. about a third of the families who fled the neighborhood of aleppo have come back. only to find out that these streets are now on the front line lines. if the regime can retake the city, it can cut off the main artery for opposition forces in aleppo and reopen a route to the airport. on a nearby hill top, the neighborhood, the rebels used to control that as well, but lost it a month ago. the battle lines here are constantly fluid. and snipers are a constant threat. the front line is visible just through here. and we can barely make out three bodies. the rebel fighters are telling us that there are two male and one female. there were five. they managed to extract two, but they can't reach the others. for the children here, gunfire has become background noise. this 12-year-old hardly notices. she says she's not afraid anymore. to start with, little hala is also chatty. but then gets sca